Sound processing unit, sound processing system, audio output unit and display device

ABSTRACT

Practical speaker connection is identified using a device having a sound channel of a 5.1 channel or 7.1 channel, and a device is provided that can easily reproduce the optimum multiple channels. Actual speaker arrangement can be identified by, for example, measuring the impedance of a terminal at the side of an audio amplifier. If incorrect connection is found, a warning is issued. This information is transmitted to a signal source with an EDID and a signal with the optimum a number of sound channel is sent. The EDID is also used for the connection with a display unit and the speaker connection with which the display unit is provided uniquely. For example, a sound through the 7.1 channel is easily reproduced using the speaker of the display unit in the channel of the front speaker.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of, and claims priority to, U.S.patent application Ser. No. 11/703,300, entitled “SOUND PROCESSING UNIT,SOUND PROCESSING SYSTEM, AUDIO OUTPUT UNIT AND DISPLAY DEVICE,” filedFeb. 6, 2007, which is a continuation of, and claims priority to, U.S.patent application Ser. No. 10/346,379, entitled “SOUND PROCESSING UNIT,SOUND PROCESSING SYSTEM, AUDIO OUTPUT UNIT AND DISPLAY DEVICE,” filedJan. 15, 2003, which claims priority to Japanese application2002-093545, filed Mar. 29, 2002, each of which is hereby incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates to an art for clearly reproducing soundsignals of multiple channels (for example, 5.1 channel and 7.1 channel)obtained from television broadcasting or a storage device, such as a VCR(Video Cassete Recorder), a DVD (Digital Versatile Disc), or a hard discrecorder. Various embodiments can be applied to a broadcasting receivingunit (hereinafter referred to as an STB (set-top-box)) that receivestelevision broadcasting and outputs a sound signal and a video signal, asound signal source (needless to say, the video signal can also beoutput), a sound processing unit, such as a switcher, for processing asignal from this sound signal source and distributing the signal tomultiple speakers, or a display device, such as a television receiver.

2. Background and Related Art

In television broadcasting and package media, such as movie softwareproducts, the digitalization of video and sound signals is advancing.The realization of multiple channels in a digital sound signal advances.For example, some DVD audio includes what is referred to as 5.1 channelsound, in which five channels (typically including the front left (FL),the front right (FR), the center (C), the rear left (RL), and the rearright (RR)) and a sub woofer (S) are used for reproducing sound.Further, 7.1 channel audio can further include a front left center (FLC)and a front right center (FRC) speaker.

When the realization of multiple channels of a sound signal advances inthis manner, the connection of a speaker cable becomes complicated andthere is a possibility of incorrect connection. As a first prior art forsimplifying the connection work of many speakers, for example, the artdescribed in Japanese Patent Laid-Open No. 2001-25085 is generallyknown. It is disclosed in this literature that when a speaker of the 5.1channel is connected, the arrangement of the speaker is judged with atest signal output from the speaker, and inappropriate arrangement andconnection are posted if they are found, and at the same time theconnection with the speaker is switched by an audio amplifier.

As a second prior art, for example, the art described in Japanese PatentLaid-Open No. H10 (1998)-94086 is known. It is disclosed in thisliterature that a terminal not connected to a speaker is detected and asound signal to be supplied to the speaker is allocated to anotherspeaker.

BRIEF SUMMARY OF THE INVENTION

In the aforementioned first prior art, however, a method ofautomatically taking action only by a warning indication was notsuggested when some speakers are not connected to a sound signalprocessing unit. For example, even if a switcher with an audio amplifierthat is one of sound signal processing units corresponds to a 5.1channel, there is a possibility of a sound effect becomingunsatisfactory when the user does not perform appropriate processing.

In a second prior art, processing is performed automatically, and amanual instruction for sound processing is not required. In the secondprior art, however, sound signal allocation processing is performed onlyin the audio amplifier. Accordingly, for example, even when a soundsignal source connected to an audio amplifier cannot identify a speakernumber connected to the audio amplifier, and when multiple sound signalssuch as a stereophonic sound system and the 5.1 channel can be supplied,an appropriate sound signal cannot be supplied.

Further, it was not taken into consideration in the aforementioned firstand second prior arts that even a speaker originally installed in adisplay device, such as a television receiver, is utilized, and adisplay unit of a display device is utilized when the speaker isconnected.

Embodiments in accordance with the present disclosure are made inconsideration of the aforementioned and other such problems. An objectof the present invention is to provide an art for transmitting aconnected state of a speaker connected to a sound processing unit to asound signal source and requesting sound data suitable for the connectedstate, and enabling the reproduction of a sound suitably. Further, thepresent invention provides an art that enables the reproduction of moreexcellent sound by utilizing even a speaker installed in a displaydevice. Moreover, the present invention provides such an art that caneasily check the connection of a complicated multi-channel speakerutilizing the display unit of the display device.

To achieve the aforementioned object, the present invention is providedwith a detection circuit that detects a connected state of a speaker foreach output terminal of a sound signal that corresponds to multiplesound channels and a control circuit for sending information about theconnected state of the speaker, for example, to a sound signal source,such as an STB, in a sound signal processing unit, such as a switcherunit. The configuration of this sound processing unit can also beprovided in a display device, such as a television receiver.

The sound signal source receives the information about the connectedstate of the aforementioned speaker and controls a number of soundchannel supplied to the sound processing unit based on the inputinformation.

Specifically, the aforementioned sound processing unit, if it isdetected by the aforementioned detection circuit that the speakers ofspecific channels (for example, the front right (FR) channel and thefront left (FL) channel, and/or the center (C) channel) are notconnected ought also be configured so that the sound signals of thesespecific channels can multiplex with video signals and reproduced by thespeaker that belongs to the display device.

Further, to connect a speaker, it is desirable that an OSD (On ScreenDisplay) circuit is provided, and a visual message regarding theconnected state of the speaker should be supplied to the user throughthis OSD circuit using a detection result by the detection circuit. Thismessage ought also to include the information that indicates theincorrect connection of a speaker and the presence of the speakerconnection, for example. Further, to display the arrangement of thespeaker by the aforementioned OSD circuit and issue a test sound signalto each speaker, an indication for visually judging the speaker undertest ought also to be performed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a device block diagram showing an embodiment of the presentinvention;

FIG. 2 is a device block diagram showing another embodiment of thepresent invention;

FIG. 3 is a device block diagram showing another embodiment of thepresent invention;

FIG. 4 is a block diagram of a signal source and a switcher used in thepresent invention;

FIG. 5 is another block diagram of the signal source and the switcherused in the present invention;

FIG. 6 is a block diagram of a display unit used in the presentinvention;

FIG. 7 is a drawing showing a display example in the display unit usedin the present invention;

FIG. 8 is another drawing showing the display example in the displayunit used in the present invention;

FIG. 9 is a device block diagram showing another embodiment of thepresent invention;

FIG. 10 is a block diagram of the signal source and a built-in signalsource switcher used in the present invention;

FIG. 11 is another block diagram of the signal source and the switcherused in the present invention; and

FIG. 12 is another block diagram of the display unit used in the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention are described below with referenceto the drawings. FIG. 1 is a device block diagram showing an embodimentof the present invention. The device of this embodiment has a displaydevice 1, a sound reproducing apparatus 2, and a signal source 3. Thedisplay device 1 and the sound reproducing apparatus 2 are mutuallyconnected through an audio/video signal transmission line 231 includinga plug and play function. This transmission line may also be aninterface with sound transmission line and video transmission line likeDVI 1.0 (Digital Visual Interface version 1.0) established by the DDWG(Digital Display Working Group) that is the connection specificationbetween a PC (Personal Computer) itself and a display device. Further,the transmission line may also be an interface for multiplexing adigital video signal and a digital sound signal.

Besides, in the following explanation of this embodiment, the “plug andplay function” allows a signal sending unit to grasp characteristic dataof a signal receiving unit without personal assistance and toautomatically send the optimum signal to the signal receiving unit whenthe signal sensing unit and the signal receiving unit are connected witha cable.

The embodiment is devised so that a speaker in a state in which it canfunction practically can be posted to an audio/video signal source.Further, when a state of speaker connection changes, the embodiment isdevised so that the audio/video signal source can identify this stateand the audio output suitable for a new state can be obtained even inoperation.

First, a switcher 201 measures the impedance of a load in each terminalto which speaker cables 220 to 225 are connected and detects thepresence of speaker connection. Such a strict measurement is notnecessary only for the presence, but even a method of providing a signalsource having output impedance and roughly measuring a voltage thatappears in a terminal is acceptable. Further, for example, because a subwoofer 210 is a special speaker that reproduces a low-pitched sound, itis designed to be different in internal impedance from another speaker.Otherwise, if high frequency impedance is reduced by connecting betweeninput terminals using a capacitor, the type of the speaker as well asthe presence of the connection can be judged and incorrect connectioncan be detected.

Besides, as described later, because the system of the present inventionis characterized by having a display unit 101, the detected speakerconnection is shown in the display unit, and a warning can be indicatedif there is an incorrect connection. Further, for example, although theRL (rear left) speaker is connected in the speakers at the rear side,the RR (rear right) speaker is not connected. At this occasion, thisindication warns that RR speaker is not connected. Moreover, a messageindicating that a signal in which the RL and RR speakers are added isoutput from the RL speaker side can also be posted.

Further, for example, when a speaker is connected to the 5.1 channel,the layout drawing of a typical speaker is displayed on the display unit101 and a test signal is sent to every speaker. Simultaneously, even thelayout error of the speaker can simply be identified by having afunction that displays the speaker on the display unit, such asblinking, and lets the user to check whether there is a conflict with adirection where a sound comes practically.

Subsequently, after a speaker to which the switcher 201 is connectedpractically is detected, the configuration for posting this speaker toaudio/video signal sources 301, 302 is described. This is performed toimplement the plug and play function by adding information about speakerconnection to an EDID (Extended Display Identification Data) establishedby the VESA (Video Electronics Standards Association) as an identifier,for example. This EDID shows the specifications (a supportablehorizontal frequency range and a pixel number) of a display device. Thatinformation about the connected state of the speaker is added to thisEDID signal and posted to the audio/video signal sources 301, 302.

A switcher sends an EDID according to a request of an audio/video signalsource. If the switcher has previously detected a speaker, it sends theEDID which has been rewritten from the initial speaker arrangement tothe practically connected speaker. Further, if the EDID has already beensent before the speaker is detected, the connections between theswitcher 201 and the audio/video signal sources 301, 302 aredisconnected once using a hot plug function and a new EDID is resentafter the speaker is detected. For this purpose, the information whetherthe EDID has already been sent or not, may be also stored in a RAM(Random Access Memory) or such. Besides, the hot plug functionoriginally indicates whether a sound reproducing apparatus and anaudio/video signal source are connected with a cable. Because shortdisconnection time, such as dozens of milliseconds, may fail to detectdesirably, the disconnection time should be approximately 0.5 to 2seconds if accurate operation is taken into consideration. A devicefunction is interrupted in this disconnection time. If a hot plug lineis prepared independently, a virtual disconnection which only hot plugline is disconnected and an audio/video transmission line keep toconnect, is available. This virtual disconnection technique providesseamless transmission of video and sound signals can also continue.

Against the case where there is no hot plug function, it is still moreconvenient that an audio/video signal source should be provided with afunction of cyclically reading EDID every predetermined time, forexample, approximately 0.5 to 2 seconds.

Subsequently, the audio/video transmission line 231 with a plug and playfunction is described. The case where neither FR speaker 211 or FLspeaker 212 is connected nor found is taken into consideration withreference to the device block diagram of FIG. 2. The speaker marked byoblique lines in the diagram is connected by a speaker cable. Thespeaker cables 221, 222 are drawn by a dashed line in the diagram, andnot connected as marked by an X mark. These two speakers 211, 212 areindispensable for obtaining a sound field with a correct ambience.Accordingly, when the aforementioned switcher 201 with an audioamplifier detects that these speakers are not connected, the switcher201 sends sound signals for the FR and FL channels to the display unit101, thereby to reproduce a sound by a front-right speaker 111 and afront-left speaker 112 of the display unit.

This can eliminate defects caused by missing the front main speakers.The switcher 201 can identify whether a speaker is connected to thedisplay unit 101 or not by reading an EDID transmitted via theaudio/video transmission line 231. For that purpose, The display unit101 should have a function of detecting whether the aforementionedspeaker is connected practically or not. Besides, when the FR speaker211 and the FL speaker 212 are connected, the front-right speaker 111and the front-left speaker 112 of the display unit need not be used. Inthis case, the switcher 201 should send mute data or the sound signalwhose level lowers rather than usual ought to be sent, or stop to send asound signal to the display unit 101.

Further, as described previously, it is easily understood for the userto display the layout drawing of the speaker shown in FIG. 2 in thedisplay unit 101 at device startup and display the presence of eachspeaker connection. For this purpose, an OSD (On Screen Display) circuitfor displaying a drawing and a character ought to be provided in theswitcher 201.

In the example of FIG. 2, if a sound of the 5.1 channel is generatedfrom the audio/video signal source 301 or 302, the sound of the 5.1channel can be reproduced using the speakers 111, 112 of the displayunit. Accordingly, when it is detected that the speakers 211, 212 arenot connected, the guidance as shown typically in FIG. 7, on the displayunit 101 may be useful.

Even if the speakers 211, 212 of the FR and FL channels are connected asa modification of the aforementioned item, when the central speaker 210of the C channel is not connected, the switcher 201 sends a sound signalof the C channel and ought also to be able to reproduce a sound by thefront-right speaker 111 and the front-left speaker 112 of the displayunit or either of them. Accordingly, a sound field with an ampleambience can be obtained using the speaker of the display unit 101.

At present, the sound of the 5.1 channel that uses the FR, FL, C, RR,RL, and S channels can be reproduced using a DVD. In the future,however, to increase the ambience, the sound of the 7.1 channel to whichthe two channels of the front right center (FRC) channel and the frontleft center (FLC) channel are added are assumed to be used. If thespeakers of the FR and FL channels are connected, the sound of the 7.1channel ought to be reproduced by using the speaker of the display unitthat is easily located nearer to the center than these speakers in theFRC and FLC channels. The switcher 201 detects using the aforementionedmethod that the speaker of the 5.1 channel is connected. Further, theswitcher 201 detects an EDID transmitted via the audio/videotransmission line 231 and identifies that the speaker is connected tothe display unit 101. Further, when the sound signal of the 7.1 channelis sent from the audio/video signal source 301 or 302, the sound signalsof the FRC and FLC channels among them are sent to the display unit 101via the audio/video transmission line 231. Besides, when the signal ofthe 7.1 channel can be reproduced in the aforementioned manner, if thesound signal from the audio/video signal source 301 or 302 belongs tothe 5.1 channel, for example, the switcher 201 ought also to performmatrix operation and artificially produce the signals of the FRC and FLCchannels, then send them to the display unit 101.

Besides, when the speakers 111, 112 of the aforementioned display unit101 are utilized, the sound signals supplied to these speakers can besent by the audio/video transmission line 231 together with videosignals through this single transmission line. Accordingly, a speakercable need not be drawn around every speaker and wiring is simplified.

Subsequently, the case where only the speaker 211 of the FR channel isnot connected is taken into consideration with reference to the deviceblock diagram of FIG. 3. Needless to say, a sound field with a normalambience is not obtained as it is. At this occasion, after the switcher201 detects that the speaker 211 is not connected, the menu showntypically in FIG. 8 ought also to be displayed. The user selects anumber in the drawing, using a remote controller, for example. In FIG.8, when 1 is selected, a sound is reproduced by a 2-channel stereophonicsound system using the speakers 111, 112 connected to the display unit(monitor). When 2 is selected, the sound is reproduced through the 5.1channel using the speakers 111, 112 as the main speakers together withthe speakers 210, 213, 214, 215 without using the speakers 211, 212.When 3 is selected, the sound is reproduced through the 5.1 channelusing the speakers 211 to 215 assuming that the user connects thespeaker 211. Further, when 4 is selected, the sound is reproducedthrough the 7.1 channel using the speakers 111, 112, 211 to 215 assumingthat the user connects the speaker 211. The sound can be reproduced inaccordance with the selection of the user.

These menu display and menu selection are convenient because they alsowork as countermeasures for incorrect operation of a speaker connectiondetection circuit when they can start at an optional timing according toa user instruction, for example, using a remote controller as well aswhen the speaker connection detection circuit detects a change ofspeaker arrangement. Further, they ought also to be performed accordingto only the user instruction without providing a speaker connectiondetection circuit in a switcher.

If a gain for a sound signal differs between the display unit 101 andthe switcher 201 with an audio amplifier, a correct ambience cannot bereproduced. For this purpose, it is assumed that the gain value isstandardized and adjusted. In the present circumstances, however, thisstandard is not available, and this standardization is not easyespecially between the devices of different manufacturers. Because aremote controller is usually placed near by the user, a method ofincorporating a microphone in this remote controller, generating a soundby every speaker, detecting this sound, and controlling a gain so thatan optimum balance can be obtained is assumed. Further, there is also amethod of requesting the user for the optimum adjustment by generating asound, such as by issuing an instruction that indicates speakerarrangement in the display unit 101 and making the relevant speakerblink. Further, there is also a method of estimating the speakerarrangement by operating the speaker other than a speaker to be testedas microphone.

For example, when the sound of the 7.1 channel is reproduced using thespeakers 111, 112, as described previously, it is also assumed that thepower of the display unit 101 is disconnected halfway in a programconsisted of only music. In this case, a a number of sound channel to beoutput ought to be switched so that the sound of the 7.1 channel can bereproduced when the power of the display unit 101 turns on and the soundof the 5.1 channel can be reproduced when the power turns off. As towhether the power of the display unit 101 turns on or not, there is amethod of detecting the retransmission of an EDID signal indicatingspeaker non-connection via the audio/video transmission line 231 using ahot plug function and of detecting an operating state of an audio/videoinput circuit of the display unit 101 by the switcher 201 via theaudio/video transmission line 231. When the switcher 201 identifies thatthe power of the display unit is or was disconnected, the switcher 201ought also to convert a sound to the 5.1 channel by matrix operation andsend it to the respective speakers 210 to 215. Further, after theconnection between the audio/video signal source 301 or 302 and theswitcher 201 is disconnected once using the aforementioned hot plugfunction, a new EDID ought also to be sent and received. The audio/videosignal source 301 or 302 sends a sounds which is converted to the 5.1channel. As a result, a sound that is always suitable for a speakerstate can be reproduced.

Besides, desirably, the switching that uses a hot plug function shouldestimate the time of approximately 0.5 to 2 seconds if the compatibilitywhen a device of a different manufacturer is used is taken intoconsideration, and the device cannot function in the meantime. If bothof the devices are machine types of the same manufacturer, the switchingin a shorter time can be performed when it is confirmed that the devicesare of the machine types corresponding to the hot plug operation in ashort time. Because a internal control signal is sometimes sent in thevertical blanking period of a video signal, the disconnection time bythe hot plug operation can be set below the conventional three frames(approximately 200 ms) by interlace scan even if an operation margin istaken into consideration. Accordingly, an effect that the disconnectedtime can be reduced is gained.

Further, when a speaker is connected after starting to reproduce sounds,a sound cannot be reproduced from the relevant speaker as is. A newlyconnected speaker can also function by operating the hot plug functionaccording to a user instruction, loading a result from which theaforementioned speaker connection was detected newly on an EDID, andsending and receiving it between devices.

The block diagram of each component for realizing the aforementioneditem is described with reference to FIG. 4, FIG. 5, and FIG. 6. FIG. 4and FIG. 5 show the switcher 201 with an audio amplifier and theaudio/video signal source 301 (or 302) respectively, and FIG. 6 showsthe display unit 101.

First, the details are described with reference to FIG. 4. Theaudio/video signal source 301 is composed of a video signal source30101, a sound signal source 30102, a sound multiplex circuit 30103, atransmitter 30104, and a channel number control circuit 30105. Besides,an audio/video transmission line 331 with a plug and play function forconnection with the switcher 201 is practically a single bundle cable,but divided into 331A and 331B and shown for convenience' sake ofexplanation.

The video signal source 30101 sends video signal obtained fromtelevision broadcasting or a device, such as a DVD, to the soundmultiplex circuit 30103. The sound signal source 30102 sends soundsignal accompanied by this video signal to the sound multiplex circuit30103 in the same manner. A number of sound channel from the soundsignal source 30102 is determined according to the instruction of thechannel number control circuit 30105. This number of sound channel mayalso be controlled by extracting the necessary number of sound channelfrom sound data contained in the television broadcasting or a devicesuch as a DVD. Further, conversion of decreasing a number of soundchannel as the need arises or conversion of increasing the number ofsound channels by producing a signal artificially may also be performed.The instruction of this number of sound channel is determined with anEDID sent from the switcher 201 as described later. The video signal andsound signal multiplexed through the sound multiplex circuit 30103 aresent to the switcher 201 via the transmitter 30104.

Subsequently, the switcher 201 with an audio amplifier is composed of aswitch 20101, a receiving circuit 20102, a sound separator 20103, anadding circuit 20104, an audio output circuit 20105, a speakerconnection detector 20106, a controller 20107, an OSD circuit 20108, afirst EDID generation circuit 20109, a second EDID generation circuit20110, a switch 20111, and a sound multiplex circuit 20112. Further, theaudio/video transmission line 231 with a plug and play function forconnection with the display device 1 is practically a single bundlecable, but divided into two lines and shown for convenience' sake ofexplanation. The speaker cables 220 to 225 are independent in the samemanner as FIG. 1 respectively.

The signal sent from the audio/video transmission line 331A with a plugand play function to the switcher 201 with an audio amplifier is firstassigned to the switch 20101. This switch is used for the aforementionedplug and play function. For example, when an EDID is sent to post itsown state between the devices at device power startup or when speakerconnection is detected in operation and it is detected that theconnection was changed, then the EDID is sent, the switch 20101 isopened once (approximately up to 2 seconds). The opening and closingtiming is assigned from the controller 20107. The switch is closed atnormal use and an audio/video signal is assigned to the receivingcircuit 20102. Besides, the open circuit of the switch 20101 is showntypically. If at least there is an open circuit or a level change in ahot plug terminal, the sending and receiving operation of theaudio/video signal can continue. A hot plug function may be realized ahot plug line independent from an audio/video transmission line.

Subsequently, a video signal and a sound signal are separated throughthe sound separator 20103. The former is assigned to the adding circuit20104 and the latter is assigned to the audio output circuit 20105.Further, a number of sound channel of the sound signal receivedpractically is posted to the controller 20107. The audio output circuit20105 ought also to correspond to the 7.1 channel, for example, but,here, corresponds to the 5.1 channel in the same manner as FIG. 1.

The speaker connection detector 20106 according to the present inventionis provided in the output of each channel and detects the presence ofconnection by measuring the impedance of a speaker connection terminal.In accordance with the result, the controller 20107 judges the number ofsound channel of a sound most suitable for being reproduced and gives aninstruction to the switch 20111. An EDID that can specify the optimumsound channel is selected from the first EDID generation circuit 20109and the second EDID generation circuit 20110 and sent to the audio/videosignal source 301. Needless to say, EDID are not limited to 2 types, butmultiple EDID ought also be selected. Multiple whole EDID data need notbe provided, but only multiple EDID data regarding a number of soundchannel ought also be prepared and switched.

Further, to display the characters as shown previously in FIG. 7 andFIG. 8 and display the connection drawing as shown in FIG. 2 and FIG. 3,the controller 20107 sends an instruction to the OSD circuit 20108 andgenerates a necessary display signal, then assigns the signal to theaddition circuit 20104. The signal is here added to or substituted for avideo signal from the sound separator 20103. Besides, while display isbeing performed through the OSD circuit 20108, if information that iscurrently being broadcast is received, this information ought also beoverlapped and displayed as a background image. When a reproductionimage, such as an image obtained from a DVD is transmitted, however,this reproduction operation ought also to stop temporarily. The outputof the addition circuit 20104 is assigned to the sound multiplex circuit20112.

To reproduce a sound using the speakers 111, 112 of the display device 1as shown in the embodiments of FIG. 2 and FIG. 3, the aforementionedcontroller 20107 gives an instruction to the sound multiplex circuit20112 and multiplex a necessary 1- or 2-channel sound signal with avideo signal, then sends it to the display device 1. A sound signalselects only the C channel or the FR and FL channels in accordance withthe connected speaker number of the display device 1. Further, in thecase of the 7.1 channel, the FRC and FLC channels may also be selectedor the FRC and FLC channels may artificially be produced and sent fromthe sound signal of the 5.1 channel.

FIG. 4 shows an example in which a signal is fetched in parallel from apart of speaker connection terminals and input to the sound multiplexcircuit 20112, but the output of the sound separator 20103 ought also beinput directly to the sound multiplex circuit 20112. The speakerconnection terminal is mostly an analog signal, and, therefore, thisterminal is advantageous when the sound separator 20103 and the soundmultiplex circuit 20112 handle digital data. In FIG. 10 described later,the output of the sound separator 20103 ought also to be input to thesound multiplex circuit 20112 via the sound selector 20205.

Besides, whether the speaker of the display device 1 is connectedpractically or not is transmitted to the controller 20107 as EDID bysimilar means on the side of the display device 1 as described later.The controller 20107 determines an instruction to the aforementionedsound multiplex circuit 20112 based on these means.

FIG. 5 shows a block diagram in which the practical speaker connectionis detected in the present invention, but a function of positivelyutilizing the speaker of the display device 1 is omitted. The soundmultiplex circuit 20112 is omitted (from FIG. 5) in comparison with FIG.4.

FIG. 6 is a block diagram showing an embodiment of the display unit 101in the present invention. Because the configuration of FIG. 6 is thesame as the switcher 201 of FIG. 4 and FIG. 5 except that a displayportion 10112 is provided and a sound signal is assigned to two speakers111, 112, a detailed explanation is omitted. FIG. 6 is characterized byhaving a speaker connection detection circuit 10106 for detectingwhether the speaker having the display unit 101 is connected practicallyand being capable of receiving the optimum sound signal as describedpreviously by sending the result to a control circuit and generating anEDID that posts a practically connected state to the switcher 201. Theconfiguration of FIG. 6 is the same as the aforementioned switcher 201regarding that a switch 10101 for a plug and play function is providedand the EDID signal generation circuit is not limited to two.

In the aforementioned explanation, as illustrated as an EDID-RAM 20206in FIG. 10 described later, if the EDID signal generation circuitconsists of a RAM (random access memory) or a flash RAM and the contentsare rewritten by a control circuit composed of a CPU and such, a singlegeneration circuit can further generate many types of signals.

Subsequently, another embodiment of the present invention is describedwith reference to the device block diagram of FIG. 9. The point thatdiffers from FIG. 1 is that the switcher 201 with an audio amplifier ofFIG. 1 is divided into another component, such as an audio amplifier 202and a switcher 203, in FIG. 9. In this case, regarding the audio/videotransmission line 231 with a plug and play that supplies a signal to thedisplay unit 101, if this line is connected to the switcher 203, thesame operation as FIG. 1 is enabled. Further, the speakers 210 to 215are connected to the audio amplifier 202 via the speaker cables 220 to225 in the same manner as FIG. 1. Accordingly, the switcher 203 has afunction of allocating a signal from the audio/video signal sources 301,302. The switcher not only sends a video signal to the display unit 101,but also, as shown in the embodiment in which each channel of a soundsignal is described previously, is divided into the audio amplifier 202and the display unit 101 and sent in accordance with the practicallyconnected state of the speaker.

Operation varies with whether a sound transmission line 232 to which theaudio amplifier 202 and the switcher 203 are connected has a plug andplay function or not. First, when a function is provided, this functionis newly implemented between the audio amplifier 202 and the switcher203. Another function is the same as FIG. 1. On the other hand, if thefunction is not provided, the user posts the speaker connected to theaudio amplifier 202 practically to a device. For example, a method ofinputting a channel that is connected using a remote controller orchanging a display unit into a touch panel type one, issuing anindication as shown in FIG. 2, and entering data by touching the mark ofthe connected speaker is assumed.

Besides, in each embodiment, the case where there are two speakershaving the display unit 101 is described as an example. Even if one orthree speakers are provided, the present invention can apply to them,and multiple-channel sound reproduction can be realized using thesespeakers in the same concept as the description of the presentinvention.

Subsequently, another embodiment of the present invention is describedwith reference of the device block diagram of FIG. 10. The case where anaudio/video signal source, such as a DVD, an STB and so on, areincorporated in the switcher 201 with an audio amplifier of FIG. 1 isassumed. In FIG. 10, 20201 is a video signal source, 20202 is a soundsignal source, 20203 is a video signal selector, 20204 is a sound signalselector, 20205 is a sound selector, and 20106 is an EDID-RAM. The samecomponent as shown in FIG. 4 is shown assigning the same number to it.

In FIG. 10, the EDID-RAM 20206 is used, but, as described in theexplanation of FIG. 4, the same operation as the case where the multipleEDIDs of FIG. 4 are switched is performed. Further, the sound selector20205 is provided. A sound signal transmitted from the output of thesound separator 20103 to the display device 1 is extracted and sent tothe sound multiplex circuit 20112. Basically, however, the operation isthe same operation as FIG. 4. Because the same operation as FIG. 4 isperformed to the external signal source 301 in particular, anexplanation of operation is omitted.

When the switches 20203 and 20204 select the video output of theinternal video signal source 20201 and the audio output of the internalsound signal source 20202, EDID data need not be sent and received. Acontroller 20107 directly controls (not shown) the sound signal source20202 and sets the optimum a number of sound channel of a sound to bereproduced. Because another operation is the same operation as theexternal signal source 301, it is omitted.

Subsequently, another embodiment of the present invention is describedwith reference to the device block diagram of FIG. 11. In the diagram, aheadphone terminal is provided in the switcher 201 with an audioamplifier of FIG. 1. In FIG. 11, 226 is a headphone cable that connectsthe headphone terminal (not shown) and the headphone of the switcher 201and 20207 is a headphone detector. The same component as shown in FIG.10 is shown assigning the same number to it. The basic operation isomitted because it is the same as FIG. 10, and only the headphoneconnection operation is described below.

When a headphone is connected to a headphone terminal, the headphonedetector 20207 detects the connection of the headphone by opening andclosing a mechanical contact or detecting the impedance detection of theheadphone. A headphone detection signal is input to the audio outputcircuit 20105 and the sound selector 20205 and stops (mutes) the audiooutput to the speaker cables 220 to 225 and the audio output to thesound multiplex circuit 20112. Consequently, the audio output of thespeaker connected to the switcher 201 and all the speakers connected tothe display device 1 can be stopped. To stop the sound connected to adisplay device, there is also a method of sending a control signal tothe display device so that the sound volume of the display device 1 canbe reduced except that the input of the aforementioned sound multiplexcircuit 20112 is muted.

Hereupon, for example, if it is assumed that the speaker arrangement ofthe 5.1 channel is used before a headphone is connected, a number ofsound channel of a sound to be reproduced, such as the connectedheadphone is stereophonic or monaural, is decreased. The change of thisnumber of sound channel rewrites the speaker arrangement information ofthe EDID-RAM 20206 via the controller 20107 and is posted to the signalsource 301 using the hot plug function of the switch 20101.Simultaneously, the signal source 301 outputs sound data suitable for aheadphone.

Subsequently, another embodiment of the present invention is describedwith reference of the block diagram of the display unit of FIG. 12. Inthe drawing, a headphone terminal is provided in the display unit 101 ofFIG. 1. In FIG. 12, 123 is a headphone cable to which the headphoneterminal (not shown) and the headphone of the display unit 101 areconnected. Numeral 10113 is a headphone detection circuit and 10114 isan EDID-RAM. The part in which the EDID-1 and EDID-2 of FIG. 6 areswitched by the switch 10111 is substituted for the EDID-RAM in the samemanner as the example of FIG. 10. In addition, even the same componentas shown in FIG. 6 is shown assigning the same number to it. The basicoperation is omitted because it is the same as FIG. 6, and only theheadphone connection operation is described below.

When a headphone is connected to a headphone terminal, the headphonedetection circuit 10113 detects the connection of the headphone byopening and closing a mechanical contact or detecting the impedance ofthe headphone. A headphone detection signal is input to the audio outputcircuit 20105 and the sound selection circuit 10105 and stops (mutes)the audio output to the speaker cables 121, 122. Consequently, the audiooutput of the speaker connected to the display unit 101 can be stopped.

Hereupon, for example, when it is assumed that a speaker is notconnected before a headphone is connected, a sound reproduction functionis added by connecting the headphone. This change rewrites the speakerarrangement information of the EDID-RAM 10114 via control 10107 and isposted to a sound processing unit (not shown), such as an audio outputunit and a switcher, using the hot plug function of the switch 20101. Adisplay unit receives sound data suitable for a headphone and a sound isreproduced by the headphone. Further, if the sound processing unitconnected to the audio/video transmission line 231 with a plug and playfunction is an audio amplifier to which speakers are connected, theaudio output of these speakers need to be stopped at the same time.Accordingly, the speaker arrangement information of the aforementionedEDID-RAM can be posted to the audio amplifier when it is rewritten.

Further, if the dedicated control line and remote controller are usedjointly though they are not shown, a speaker can be muted by directlycontrolling an audio amplifier. The method of jointly using the controlline and the remote controller is effective when a stereophonic speakercannot be distinguished from a stereophonic headphone. In this case, ifthe stereophonic headphone is connected, the speaker arrangement of theEDID-RAM is identical when the stereophonic speaker is connected to thedisplay unit 101.

In the explanation of the aforementioned embodiment, the switcher 201 isseparated from the audio/video signal source 301 or 302 or the displaydevice 1, but even the configuration in which the audio/video signalsource 301 or 302 or the display device 1 is incorporated in theswitcher 201 ought to be acceptable. In this case, the configuration inwhich connection information is sent from the switcher 201 to theaudio/video signal source 301 or 302 is omitted, but the configurationof number of sound channel control that corresponds to the detectedconnected state is identical with that of the aforementioned embodiment.

Further, when a television broadcasting signal has program information,a number of sound channel ought also be controlled based on the programinformation. Program information is used to display an electronicprogram guide on a display. This program usually indicates a schedule ofa program in the future of each channel. Further, program informationincludes a program title, a name (number of sound channel) of abroadcasting station, broadcasting start and end times of a program,types (movie, news, and drama) of the program, and data regarding thenumber of sound channel of a sound reproduced in the program.

The broadcasting signal of news program usually has the sound signal ofthe 2 channel. The broadcasting signal of movie and music program oftenhave the sound signal of the 5.1 channel or 7.1 channel. Accordingly,the data indicating that the number of sound channel is the 2 channelmay be added to the broadcasting signal of news, and the data indicatingthat the number of sound channel is 5.1 channel or 7.1 channel may beadded to the broadcasting signals of movie and music programs.

Accordingly, as another embodiment of the present invention, the soundsignal source 30102 ought also be controlled in a channel number controlcircuit by extracting program information from the broadcasting signalof the program selected by the user in accordance with the data of thenumber of sound channel contained in the extracted program information.Accordingly, when a news program is selected and the data indicatingthat the number of sound channel is the 2 channel is added to thebroadcasting signal, a sound is reproduced through the 2 channel even ifa device is provided with the speaker of the 5.1 channel. On the otherhand, when a movie program is selected and the data indicating that thenumber of sound channel is the 2 channel is added to the broadcastingsignal, and the device is provided with the speaker of the 5.1 channel,the sound is reproduced by utilizing all speakers. Such configurationcan realize automatic control of the number of sound channel inaccordance with the contents of the program.

Moreover, in the present invention, if the program with 2 channel audiosignal is indicated as a “movie” program information which the programcontains, the program can be reproduced artificially through the 5.1channel. Further, if the program with 7.1 channel audio signal isIndicated as “news” in a program information in which the programcontains, the program can be reproduced artificially through the 2channel. That is, this embodiment is characterized by using the data ofthe program type more preferentially than the number of sound channeldata contained in program information as data for determining a numberof sound channel of a sound to be reproduced.

More specifically, the audio/video signal source 301 including areceiver of a television broadcasting signal reproduces a sound throughthe 5.1 channel or 7.1 channel when the program information indicates a“movie”. The source 301 reproduces a sound through the 2 channel whenthe program information indicates “news”. For these function, a table isconstructed by presetting the data of the appropriate number of soundchannel of a sound to be reproduced every program type. The data tableis used to set the number of sound channel of a sound to be reproduced.The aforementioned table can be stored in a microcomputer memory oranother memory that is not shown. The audio/video signal source 301(built-in microcomputer) extracts program information from the receivedtelevision broadcasting signal and judges the contents of the data of aprogram type contained in the program information. The judgment resultis referred to with the table stored in the aforementioned memory andthe microcomputer reads the data of a number of sound channel of a soundto be reproduced that corresponds to the judged program type from theaforementioned memory. Using this data of the number of sound channel ofthe sound to be reproduced, the program sound number of sound channelcontrol circuit controls the sound signal source 30102 and controls thenumber of sound channel of the sound to be reproduced. Suchconfiguration can reproduce a sound in appropriate number of soundchannel in accordance with a program type. Regarding the number ofreproduced sound channel control that uses the aforementioned table, theuser ought to be able to select permission/prohibition. At that time,desirably, using an OSD circuit, a message regarding the selection oughtto be displayed on a display and processed interactively with the user.

According to the present invention, a multiple-channel sound signal cansuitably be reproduced in accordance with a connected state of aspeaker. Further, besides the speaker connected to a switcher and such,the speaker of a display device can be used jointly and a higher soundeffect can be obtained. Further, because the connected state of thespeakers are displayed on the display device, an user would easily andaccurately connects the speakers.

1. A sound processing unit for receiving a sound signal from an externalsound outputting unit and outputting the received sound signal to aspeaker, comprising: an obtaining unit operable to obtain soundinformation relating to a condition of a sound output; a memory operableto store the sound information obtained by the obtaining unit; acommunication unit operable to communicate with an external soundoutputting unit; and a controller operable to control the communicationunit so as to transmit the sound information stored in the memory whenthe obtain uniting obtains a change of the sound information relating tothe condition of the sound output.
 2. The sound processing unitaccording to claim 1, wherein the memory stores specificationinformation for the sound processing unit, the communication unit beingfurther operable to transmit the specification information together withthe sound information stored in the memory.
 3. The sound processing unitaccording to claim 1, wherein the sound information is a connectioncondition of a speaker connected to the sound processing unit.
 4. Thesound processing unit according to claim 1, wherein the communicationunit is further operable to transmit the sound information stored in thememory as a control signal for the external sound outputting unit. 5.The sound processing unit according to claim 4, wherein the controlsignal is for converting a number of sound channels of the sound signalfrom the external sound outputting unit.
 6. The sound processing unitaccording to claim 1, wherein the communication unit includes a hotplug, the controller being further operable to control the hot plug soas to notice the change of the sound information to the external soundoutputting unit, the communication unit being further operable toreceive a requirement from the external sound outputting unit inresponse to the change, and transmit the sound information stored in thememory in response to the received requirement from the external soundoutputting unit.
 7. The sound processing unit according to claim 1,wherein the sound information further includes second sound informationof an external display apparatus connected to the sound processing unit.8. A sound processing unit for receiving a sound signal from an externalsound signal source and outputting the received sound signal to aspeaker, comprising: an obtaining unit operable to obtain first soundinformation relating to a condition of sound output of an externalapparatus connected to the sound processing unit; and a communicationunit operable to transmit sound output information based on the firstsound information obtained by the obtaining unit and second soundinformation relating to a condition of the sound processing unit to theexternal sound signal source.
 9. The sound processing unit according toclaim 8, further comprising: a memory operable to store the first andsecond sound information, wherein the communication unit is operable totransmit the first and sound information read out from the memory. 10.The sound processing unit according to claim 8, wherein the externalapparatus is a display apparatus including a speaker.
 11. The soundprocessing unit according to claim 8, further comprising: a controlleroperable to control the communication unit so as to transmit the soundoutput information in response to a requirement from the external soundsignal source.
 12. The sound processing unit according to claim 8,further comprising: a controller operable to control the communicationunit so as to transmit the sound output information when changing thefirst or second sound information.